Our fundamental goals in this project are: (a) to understand the mechanisms operative in the absorption, utilization, storage, and excretion of trace metals by mammalian systems with particular interest to iron metabolism; and (b) to apply this understanding to the detection and prevention of pathological and nutritional disorders of iron metabolism. Our research methods include: (a) physical-chemical characterization of the solution chemistry of iron chelates and hydroxy-iron(III) polymers; (b) magnetic and optical spectroscopy of interactions of iron(III) with proteins and ligands of endogenous and dietary origin, e.g., mucoproteins and phosphoproteins; (c) measurement of iron assimilation in small animals by whole-body retention of iron-59, accumulation of liver ferritin by chemical and immunoradiometric assay, and tests in which the excretion of a cobalt-60 probe is related to the level of dietary iron; (d) measurement of iron flux across isolated intestinal mucosa isolated from intact gut to quantitate the mucosal regulation of iron absorption. The results of these investigations will be applied to the design of rational and expeditious methods for facilitating and regulating the absorption of dietary and therapeutic levels of iron. BIBLIOGRAPHIC REFERENCES: Carmichael, D., J. Christopher, J. Hegenauer, P. Saltman. 1975. Effect of milk and casein on the absorption of supplemental iron in the mouse and chick. Am. J. Clin. Nutr. 28:487-493. Christopher, J., L. Hatlen, J. Hegenauer, L. Ripley, P. Saltman, and C. Ward. 1975. Radioimmunoassay of ferritin in rat serum: correlation of serum ferritin with liver ferritin iron stores. In: Proteins of Iron Storage and Transport in Biochemistry and Medicine. Crichton, R.R., ed. North-Holland Publishing Co.: Amsterdam. pp. 411-416.